<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../jq/jquery-3.2.1.js"></script>
</head>

<body>
  <button>按键1</button>
  <button>按键2</button>
  <button>按键3</button>
  <button>按键4</button>
  <button>按键5</button>
  <button>按键6</button>
  <script>
    $(function () {
      $('button').click(function () {

        $(this).css({
          'backgroundColor': 'red'
        })

        $(this).siblings('button').css({
          'backgroundColor': ''
        })
      })
    })
  </script>
</body>

</html>